The present invention relates to a belt tensioner in an occupant restraint system which has a safety belt one end of which is anchored to the vehicle body.
Such belt tensioners usually comprise a piston/cylinder linear drive which has a pyrotechnic propellant charge. One of the known types of belt tensioners (DE 30 44 951 A1) engages directly on the belt webbing, in order to form a belt webbing loop due to which the effective belt webbing length is reduced. The belt webbing loop is formed between a pair of deflector elements mounted on the vehicle body.